Chilabothrus Dumeril & Bibron, 1844

Szyndlar, Zbigniew & Georgalis, Georgios L., 2023, An illustrated atlas of the vertebral morphology of extant non-caenophidian snakes, with special emphasis on the cloacal and caudal portions of the column, Vertebrate Zoology 73, pp. 717-886 : 717

Chilabothrus Dumeril & Bibron, 1844

Material examined

Chilabothrus angulifer (Bibron, 1840 in Ramón de la Sagra, 1838-1843) (MNHN-ZA-AC-1892.0089; SMF PH 61); Chilabothrus subflavus (Stejneger, 1901) (SMF PH 32).

Description.

Trunk vertebrae. Centrum shorter than wide; cotyle and condyle orbicular; posterior median notch of the neural arch deep; neural spine as high as long in lateral view; in Chilabothrus angulifer , neural spine is very thick in dorsal view; prezygapophyses slightly dorsally inclined in anterior view; prezygapophyseal accessory processes vestigial; zygosphene with a prominent median lobe in dorsal view; in C. angulifer , zygosphene possesses a distinct median ridge in anterior view, while it is very thin in Chilabothrus subflavus ; hypapophyses diminish strongly in size after V 20 and disappear at around V 40 in C. angulifer , while in C. subflavus hypapophyses are prominent at least until V 60 and start to disappear at around the level of V 70; haemal keel in more posterior vertebrae prominent in C. angulifer but rather indistinct in C. subflavus ; paracotylar foramina absent.

Trunk / caudal transition (for Chilabothrus angulifer ). A prominent haemal keel is present in posterior trunk vertebrae and it becomes a short hypapophysis in posteriormost trunk vertebrae. Cloacal and anteriormost caudal vertebrae too possess a short hypapophysis. In succeeding caudal vertebrae, this hypapophysis diminishes in size gradually and grooved keels reminiscent of tiny haemapophyses appear in the 5th caudal vertebra. Normally paired haemapophyses first appear on the 6th caudal vertebra.

Number of vertebrae. Chilabothrus angulifer (SMF PH 61): 308 (249+5+53); Chilabothrus subflavus (SMF PH 32): 329 (282+5+42).

Data from literature: Chilabothrus angulifer : 290 trunk and cloacal vertebrae plus ~79+2 caudal vertebrae ( Alexander and Gans 1966); Chilabothrus angulifer : 284-288 trunk vertebrae plus 50-51 cloacal and caudal vertebrae ( Holman 1967); Chilabothrus angulifer : 275-283 trunk vertebrae plus 4-5 cloacal vertebrae plus 44-54 caudal vertebrae ( Machado-Filho 2020); Chilabothrus striatus (Fischer, 1856): 291-296 trunk and cloacal vertebrae plus 91-92 caudal vertebrae ( Alexander and Gans 1966); Chilabothrus striatus : 280-290 trunk vertebrae plus 3-5 cloacal vertebrae plus 55-81 caudal vertebrae ( Machado-Filho 2020); Chilabothrus striatus : 348-367 vertebrae in total ( Parmley and Reed 2003).